Who Are Literature's Scariest Characters?

From "Paper Cuts," the literary blog by The New York Times, here is list of one website's poll of literature's scariest characters:

1) Big Brother from 1984, by George Orwell
2) Hannibal Lecter from the novels by Thomas Harris
3) Pennywise the clown from It, by Stephen King
4) Nurse Ratched from One Flew Over a Cuckoo’s Nest, by Ken Kesey
5) Count Dracula from Bram Stoker
6) Annie Wilkes from Misery, by Stephen King
7) The demon from The Exorcist, by William Peter Blatty
8) Patrick Bateman from American Psycho, by Bret Easton Ellis
9) Bill Sykes from Oliver Twist, by Charles Dickens
10) Voldemort from the Harry Potter books by J.K. Rowling

I can't think of many characters I'd add to this list. If I had to name a few, I'd say Iago from Othello, Grendel from "Beowulf," and Jimmy Porter from Look Back in Anger. And although he's not scary like these others, but just because his boring and nearly pointless book is one of the few I really dislike (and in that way it, and he, scare me), I'd add Thoreau from Walden if I could.

Who would you add?